docs: def import_from_source(module_filepath):
      """
      Import a module from a particular filesystem location.
  
      :param str module_filepath: path to the file that constitutes the module
          to import
      :return module: module imported from the given location, named as indicated
      :raises ValueError: if path provided does not point to an extant file
      """
      import sys
  
      if not os.path.exists(module_filepath):
          raise ValueError("Path to alleged module file doesn't point to an "
                           "extant file: '{}'".format(module_filepath))
  
      # Randomly generate module name.
      fname_chars = string.ascii_letters + string.digits
      name = "".join(random.choice(fname_chars) for _ in range(20))
  
      # Import logic is version-dependent.
      if sys.version_info >= (3, 5):
          from importlib import util as _il_util
          modspec = _il_util.spec_from_file_location(
              name, module_filepath)
          mod = _il_util.module_from_spec(modspec)
          modspec.loader.exec_module(mod)
      elif sys.version_info < (3, 3):
          import imp
          mod = imp.load_source(name, module_filepath)
      else:
          # 3.3 or 3.4
          from importlib import machinery as _il_mach
          loader = _il_mach.SourceFileLoader(name, module_filepath)
          mod = loader.load_module()
  
      return mod